A. Look at the following pictures and discuss with your partner what you see in them. How are the two pictures related to each other?
B. Read the text and answer the following questions.
Countries of the world rely heavily on petroleum, coal and natural gas for their energy sources. There are two major types of energy sources: renewable and non-renewable. Hydro-carbon or fossil fuels are non-renewable sources of energy. Reliance on them poses real big problems. First, fossil fuels such as oil, coal, gas etc, are finite energy resources and the world eventually will run out of them. Secondly, they will become too expensive in the coming decades and too damaging for the environment. Thirdly, fossil fuels have direct polluting impacts on earth's environment causing global wanning. In contrast, renewable energy sources such as, wind and solar energy are constantly and naturally replenished and never run out.
Most renewable energy comes either directly or indirectly from the sun. Sunlight or solar energy can be used for heating and lighting homes, for generating electricity and for other commercial and industrial uses.
The sun's heat drives the wind and this wind energy can be captured with wind turbines to produce electricity. Then the wind and the sun's heat cause water to evaporate. When the water vapour turns into rain or snow and flows downhill into rivers or streams, its energy can be captured as hydroelectric energy.
Along with the rain and snow, sunlight causes plants to grow. Plants produce biomass which again can be turned into fuels such as fire wood, alcohol, etc identified as bioenergy.
Scientists have identified Hydrogen as another form of renewable energy source. It is the most abundant element in nature. But it does not exist separately as a gas. It is always combined with other elements, such as with oxygen to make water. Hydrogen, separated from another element, can be burned as a fuel to produce electricity.
Our Earth's interior contains molten lava which gives off extreme heat. This heat inside the Earth produces steam and hot water which can be tapped as geothermal energy to produce electricity for heating homes, etc.
Ocean energy comes from several sources. Ocean's force of tide and wave can be used to produce energy. The surface of the ocean gets more heat from the sun than the ocean depths. This temperature difference can be used as energy source too. (Source: the Internet)
Questions
1 What do you mean by renewable energy sources?
2 What are the problems with non-renewable energy sources?
3 What are the major differences between renewable and non-renewable energy sources?
C. Which of the renewable energy sources mentioned in the text have you heard of before? One of those resources is used in the Chittagong Hill Tracts (CHT) to produce electricity. Can you say what it is? Browse the net in groups to find out the answers to the following issues and present them to the class.
1 What is the name of the project?
2 Where in the CHT is the project located?
3 When did it start operation?
4 How much electricity is being produced from here for the national grid?
5 How many units are working there?
6 What is the positive impact of the project on our national development?
D. Read the dialogue between Raju, a student of class ten and his uncle, Mr Barua who works at Sangu Gas Field and answer the following questions.
Mr Barua : What are you reading, Raju?
Raju : English, Uncle. A chapter on renewable energy sources.
Mr Barua : I see. Do you know renewable energy is also called green energy?
Raju : Green energy?... No Uncle, I don't know. Nothing is there about green energy in the text either.
Mr Barua : Are you sure? Anyway, renewable energy sources provide us with energy which doesn't harm environment during its production or consumption. Say, solar energy. You see, there's no burning, no smoke, no emission of gases. It's a sort of clean technology and clean energy source.
Raju : Oh exactly. That's what our teacher said, I remember.
Mr Barua : On the other hand, burning fossil fuels, say oil or coal, emits greenhouse gases that harm the environment.
Raju : O... I see. Yes,I've got the clue, Uncle. Thanks a lot. I now understand the relation between the two pictures in section A. Green energy sources make a green globe. Excellent!
Questions
1 Why is renewable energy called green energy?
2 'Nothing is there about green energy in the text either'. — Do you think this statement of Raju is correct? Explain why yes/no.
3 I now understand the relation between the two pictures in section A'. What does Raju mean here? What does he really understand? Do you agree with Raju's view here? Why?
E. Read the dialogue and act it out in pairs.
A : What's solar energy?
B : It's one of the renewable energy sources.
A : Why is it called green energy?
B : Well, it's green energy because it helps us keep the Earth green. I mean it doesn't emit any pollutants in the atmosphere when we produce and use it.
A : I see. Then it must be a clean source of energy.
B : Exactly. And that's why it's also called clean energy.
Now complete the following dialogue taking cues from the above model.
A : What's wind energy?
B : It's one of the……………
A : Why's it called……………?
B : Well, it's green energy because…………… the Earth green. I mean it doesn't…………… when we produce and use it.
A : I see. Then it…………… source of energy.
B : Exactly. And that's why…………… clean energy.
F. Now write dialogues on hydroelectricity, ocean energy, geothermal energy, hydrogen energy, using the model in E above.
G. Both South and North Dhaka City Corporation are installing solar panels in place of conventional electricity connections to illuminate roads in many areas. Write a letter to the editor of a daily newspaper appreciating this initiative and saying why this should be followed by other city authorities too.
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